Just because he has a bunch of powers doesn’t mean he stronger than them. He can have all the powers in the world but he won’t be stronger. Midoriya flaw is that he rushes headlong into danger without back up. All one keeps winning is because he has people fighting for him an organized. Even Shiragi saw value and created the league of villains who have been kicking the hero’s asses. Roman was not built in one day and Midoriya no matter how powerful he is can’t do it by himself. And he clearly doesn’t know how to use the full scope of his abilities if he only appear to use smoke screen. Also, the sniper almost took him out so, and his been taking low level bad guys.
I don’t think they were saying he can do everything by himself but it’s most likely true he can beat 90% of them by himself expect maybe Todo and Bakugo thats pretty obvious
remember that midoriya has all the info of them in his ntbk right? He memorized their weaknesses and their flaws. He can defeat his classmates if he is completely in a fine state and he can control the full power of AFO. So basically he is holding back but in his current state rn he can't defeat his friends coz he probably get passed out due to exhaustion
I think you forgot that his "bunch of powers" aren't just accessories that the other OFA predecessors gave guidance to use just to appear strong. In order to survive the current situation of their country, Deku had to be able to wield and master every each and one of these "bunch of powers" and also to be able to use them together. Your "flaw" of him doesn't even make relevance to my topic, which is "UA Class A/Deku's classmates won't be able to beat him". May I remind you that UA Class A has been inactive in real combat for some time now, but I know they've been training, but during those times; Deku was fighting with top ranked heroes who turned their backs on the hero community (namely Lady Nagant), big name villains known for their wit or strength (namely Muscular) and he hasn't been fighting with one on one or one vs. two, he has fought with villain mobs and etc.
Also here's a good argument statement as to why:
https://comicbook.com/anime/news/my-hero-academia-why-class-1a-cant-beat-deku/
He's stronger than them. The only thing that is holding him back from giving it his full strength is the thought that he might hurt them.